The present invention relates to a means in a fuel system used to limit the temperature of the carburetor, conduits and other parts of an engine during after-heating which occurs when the engine has stopped.
The carburetor in eg. chain saws is of the membrane carburetor type which in contrast to a float carburetor, allows positioning of the chain saw in various positions while the saw is is operating. The membrane carburetor has, however, the disadvantage of making it more difficult to restart the engine after a short stop. This is due to the fact that the fuel chamber in the carburetor, from which the fuel is led to the air passage of it, is situated close to the cylinder. This nearness to a heat source causes the fuel in the chamber to become heated. The heated fuel in the chamber then evaporates causing an overpressure which locks the inlet valve to the chamber in a closed position. When the engine is to be started fuel is absent from the chamber and therefore the engine will not start.